Lockless atomic table update

ABSTRACT

Upon detecting a data event initiating an update to a table, a first classifier index associated with the data event is identified. From a classifier table, the current position in a first dimension of the table associated with the classifier index is determined. An open position in the first dimension of the table is also identified. Updated data is stored in the open position within the table. In the classifier table, the open position storing the updated data is associated with the classifier index.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/976,228, filed Sep. 28, 2007 and is aContinuation of U.S. patent application Ser. No. 12/240,935, filed Sep.29, 2008, the contents of which is hereby incorporated by referenceherein in its entirety.

BACKGROUND

The usage of data networks has increased tremendously over the pastdecades. With increased reliance on network-based applications,including e-commerce, on-line entertainment, voice-over Internetprotocol (VoIP) telephony, and countless others, demand on data networkswill only continue to grow. As a result of this growing demand, datanetwork performance will have to continue to increase to service thisdemand.

To support improved data network performance, routers and other trafficmanagement devices will have to direct resource requests at increasinglyhigher speeds to direct data packets or other data events between theirsources and destinations. Traffic management devices frequently usetables to facilitate packet routing: upon identifying some attributepresented by or derived from the packet, the traffic management deviceperforms a table lookup on that attribute to determine the destinationto which the packet should be routed.

One issue that may cause delays in routing packets arises when the tablemust be updated to store a new or updated destination for a packetassociated with a particular transmission. While the table is beingupdated, typically at least a portion of the table is locked and cannotbe accessed. Traffic management devices may need information in thelocked portion to route packets. However, because there may be no way tostore and then later route these packets while continuing to processincoming traffic when the table is locked, these packets may be droppedand resent. Resending the packets results in increased traffic, reducingnetwork performance.

SUMMARY

According to one embodiment, a method provides uninterrupted access to anetwork traffic handling table during table updates. The method includesidentifying a first classifier index associated with a data packetreceived by one of a plurality of traffic management devices. An initialtable position is determined from a first classifier table in a firstdimension of the network traffic handling table. The classifier tableassociates classifier indices with table positions such that the initialtable position is associated with the first classifier index. An initialopen table position is determined in the first dimension of the networktraffic handling table. Information associated with the data packet isstored within the initial open table position in the network traffichandling table. The initial open table position is associated with thefirst classifier index in the first classifier table.

According to another embodiment, a method provides uninterrupted accessto a network traffic handling table during table updates. The methodcomprises receiving a data packet in one of a plurality of trafficmanagement entities and identifying a first classifier index associatedwith the data packet. A second classifier index is identified that isassociated with the data packet. A first classifier table is accessed todetermine a first position in a first dimension of the network traffichandling table associated with the first classifier index. The firstclassifier table references positions in the first dimension of thenetwork traffic handling table that are mutually disjoint with otherpositions in the network traffic handling table managed by one or moreother traffic management entities. An open position is determined in thefirst dimension of the table associated with the traffic managemententity. Existing packet handling data is copied from the currentposition to one or more corresponding locations in the second dimensionin the open position in the network traffic handling table. Updatedpacket handling data is stored within the open position in the networktraffic handling table at a second dimension location indicated by thesecond classifier index. The open position is associated with theclassifier index in the classifier table. The open position becomes anew current position associated with the first classifier index. Thecurrent position previously associated with the first classifier indexis designated as a new open position in the network traffic handlingtable associated with the one traffic management entity.

According to yet another embodiment, a machine readable medium storesmachine executable instructions, which when executed on one or moreprocessors, causes a network traffic manager system to perform one ormore instructions. The instructions include maintaining a tableconfigured to store data in a plurality of cells existing atintersections of positions in a first dimension of the table andlocations in a second dimension of the table. A classifier table ismaintained for entities authorized to update the table. Maintaining ofthe classifier table includes associating the positions in the firstdimension of the table with a classifier index and receiving aclassifier index update to associate a previously open position in thefirst dimension of the table with a classifier index previouslyassociated with another position whose contents were superseded in theupdate. An open position indicator is maintained for the entitiesauthorized to update the table. The open position indicator isconfigured to indicate a position available to receive an update withoutwriting in the positions associated with a classifier index in theclassifier table. An open position update is received to identify theother position whose contents were superseded in the update.

According to another embodiment, a system provides uninterrupted accessto a network traffic handling table during table updates. The systemincludes a table configured to store data relating to a plurality ofdata events. The table includes a plurality of positions in a firstdimension configured to store data associated with a classifier indexand an open position configured to receive an update. A classifier tableis configured to associate a plurality of classifier indices withpositions in the table. An open position indicator is configured toidentify the open position. A traffic management entity is configured toreceive a data event, identify a first classifier index associated withthe data event, consult the classifier table to identify a currentposition associated with the first classifier index, and consult theopen position indicator to identify the open position. The trafficmanagement entity is further configured to store new data in the openposition, update the classifier table to associate the first classifierindex with the open position that has received the update, and updatethe open position indicator to identify the current position that wassuperseded by the update.

In yet another embodiment, a traffic manager device providesuninterrupted access to a network traffic handling table during tableupdates. The apparatus comprises a memory for storing a set of computerexecutable instructions, a network transceiver configured to receivenetwork traffic, and a processor configured to execute the set of storedcomputer executable instructions. The set of instructions includesreceiving a data packet, identifying a first classifier index associatedwith the data packet, identifying a second classifier index associatedwith the data packet, and accessing a first classifier table todetermine a first position in a first dimension of the network traffichandling table associated with the first classifier index. The firstclassifier table references positions in the first dimension of thenetwork traffic handling table that are mutually disjoint with otherpositions in the network traffic handling table managed by one or moreother entities. The instructions also include determining an openposition in the first dimension of the table associated with the entity,copying existing packet handling data from the current position to oneor more corresponding locations in the second dimension in the openposition in the network traffic handling table, and storing updatedpacket handling data within the open position in the network traffichandling table at a second dimension location indicated by the secondclassifier index. The instruction further provide for associating theopen position with the classifier index in the classifier table, whereinthe open position becomes a new current position associated with thefirst classifier index, and designating the current position previouslyassociated with the first classifier index as a new open position in thenetwork traffic handling table associated with the entity.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanyingfigures. In the figures, the left-most digit of a three-digit referencenumber or the two left-most digits of a four-digit reference numberidentify the FIGURE in which the reference number first appears. The useof the same reference numbers in different figures indicates similar oridentical items.

FIG. 1 is a block diagram representing an exemplary operatingenvironment in which a traffic management device directs clientrequests.

FIG. 2 is a block diagram of the traffic management device shown in FIG.1.

FIGS. 3A and 3B are block diagrams of alternative forms of trafficmanagement devices including multiple devices accessing a common table.

FIGS. 4A-4E, 5A-5B, and 6A-6B are block diagrams of an implementation ofclassifier tables used by one or more entities to perform locklessatomic updates on portions of a one-dimensional table.

FIGS. 7A-7D and 8A-8B are block diagrams of another implementation ofclassifier tables used by one or more entities perform lockless atomicupdates on portions of a two-dimensional table.

FIGS. 9 and 10 are flow diagrams of processes for performing locklessatomic updates of tables.

DETAILED DESCRIPTION

Overview

Having to lock a table or a portion of a table while it is being updatedmay result in data communications delays. The present invention allowsfor portions of tables to be updated without having to lock a table or aportion of a table. If the portions of the table are not locked for anupdate, existing information in those portions of the table may continueto be accessed during the update, helping to eliminate the delaying ordropping of packets while a needed portion of the table is locked andunavailable.

Lockless atomic updating allows for positions to be updated in a tablewithout either the complexity of placing access locks on the table orthe delays that may result from resending dropped packets that arereceived while locking tables or portions of the table. Upon determininga classifier index associated with a data event or packet, a classifiertable is consulted to determine the position in the table currentlycorresponding to the determined classifier index. Updating is performedby copying any existing data from the position in the tablecorresponding to the determined classifier index to locations in an openposition in the table, and storing the updated data in a designatedlocation in the open position. While the updating is taking place, otherentities may access the existing data in the position in the tablecurrently corresponding to the determined classifier index withoutinterruption because the update is being applied in a separate, openposition in the table. Once the update is complete, the classifier tableis updated to associate the previously open position with theclassifier. The position in the table formerly corresponding to thedetermined classifier index, whose contents were superseded by theupdate, is then made available as the new open position.

Possible Operating Environment for Lockless Atomic Updating

FIG. 1 illustrates an exemplary operating environment 100 of a trafficmanagement device 110. In the exemplary operating environment 100, aplurality of clients, including client 1 120, client 2 122, throughclient N 124, seek services provided by a plurality of servers,including server 1 160, server 2 162, through server N 164. The clients120-124 are in communication with a network 130, which may include apublic network, such as an Internet, or a private network, such as adedicated network or a virtual private network. Within the network 130,a domain name server or other routing system (not shown) identifies aresource location 140, which may include a server, a server pool, avirtual server, or another type of resource location sought by theclients 120-124.

At the resource location 140, incoming communications may be received bya network access device 150, such as a router or other switching device,which operably couples the resource location 140 with the network 130.The traffic management device 110, or “TMD,” receives from the router150 client requests for the services provided by one or more of theservers 160-164. The traffic management device 110 then directs theclient requests to one of the servers 160-164.

The exemplary operating environment of FIG. 1 illustrates just operatingenvironment in which implementations of the present disclosure may beused. For example, the network access device 150 also may utilizeimplementations according to the present disclosure, or the servers160-164 may handle their own network access and/or traffic managementfunctions. For another example, the traffic management device 110 maydirect traffic to destinations other than servers, including otherserver farms, communication systems, or other destinations. Further, theenvironment 100 may include multiple traffic management devices 110 thatmay share one or more common tables used in the management of networktraffic as described below with reference to FIGS. 3A-3B and otherFIGURES.

The following descriptions and examples are directed to the use ofimplementations of the present disclosure in association with one ormore traffic management devices. However, this disclosure is not limitedto such uses.

FIG. 2 is a block diagram of an exemplary implementation of a trafficmanagement device 110 as shown in FIG. 1. The traffic management device110 of FIG. 2 is a computing system combining both hardware and softwarecomponents. In other words, the traffic management device of FIG. 2 canbe regarded a computing system configured to perform some functions inhardware and others by executing software instructions stored in memorylocations.

Specifically, the traffic management device 110 of FIG. 2 includes sixgeneral components: a central processing unit 210, random access memory(RAM) 220, read-only memory (ROM) 240, disk storage 250, applicationspecific integrated circuits (ASICs) 260, and a network interface unit270. The central processing unit 210 is configured to executeinstructions stored in the random access memory 220 or the read-onlymemory 240 to execute the functions of the traffic management device.The random access memory 220 includes a volatile or non-volatile memorysystem that stores a plurality of programs and/or data retrievable fromdisk storage 250 or otherwise provided to the random access memory 220.

The random access memory 220 stores programs or sets of instructionsthat include an operating system 222, a load balancer 224, program code228, and user programs 230. The operating system 222 facilitates theoverall function of the traffic management device 100, includingmanaging how the traffic management device 110 interfaces with internaland external devices and processes various programs. The load balancer224, implementations of which are described below, distributes clientrequests for services to different resources, such as servers 160-164(FIG. 1) with which the traffic management device 110 is associated tobalance the workload among those resources. The program code 228 anduser program 230 facilitate other functions, such as monitoring theoperation of the traffic management device 110 or other functionssupported by the provider of the traffic management device 110 orcreated by a user of the traffic management device 110, respectively.

The read-only memory 240 stores instructions including startup routinesand other device-specific functions based on the architecture of thetraffic management device 110. The disk storage 250 stores programs anddata that will be retrieved into or stored from the random access memory220. One or more application specific integrated circuits 260 areconfigured to implement various data communications or frequently usedfunctions in hardware. The network interface unit 270 provides theconnections and control logic to receive and transmit datacommunications over a network and/or to a plurality of associatedresources.

Although the traffic management device 110 of FIG. 2 is described as acombined hardware and software system, implementations of the presentdisclosure may be used with traffic management devices that areimplemented in hardware, software, or some combination of both.

For example, the traffic management device 110 may include a pluralityof scalable components, including one or more switching components andone or more control components. In such an implementation, the switchingcomponents, for one example, may be exclusively hardware components thatreceive incoming data packets or other data events and, based oninformation associated with the data events or packets, access tables toidentify a destination to which the data events or packets should berouted. If it is determined that a data event or packet is not alreadyassociated with a destination, the switching component may direct thedata event or packet to a control component to determine a destinationto which the data event or packet should be routed. Regardless of howthe switch component is implemented, the control component may beimplemented in hardware, software, or a combination of hardware andsoftware.

FIGS. 3A and 3B depict, as previously described with reference to FIG.1, the use of multiple different traffic management devices or multipledifferent traffic management device components operating as part of aunified traffic management system. FIG. 3A shows a traffic managementsystem 300 that includes multiple traffic management devices includingtraffic management device #1 310, traffic management device #2 320,through traffic management device #N 330. The traffic management devices310-330 share the traffic management load applied to the trafficmanagement system 300. The traffic management devices 310-330 may beconfigured to accommodate data events or packets for different types oftransactions or sessions included in the load applied, or may beconfigured to share in the overall load applied to the trafficmanagement system 300.

In the implementation of FIG. 3A, the traffic management devices 310-330share in managing the load applied to the traffic management system 300.The traffic management devices 310-330 thus access a common table 340.The table 340 includes information that associates incoming data packetsor other data events with flows, servers, or other destinations to whichthe data events or packets should be directed. By sharing a common table340, regardless of which of the traffic management devices 310-330responds to a particular data event or packet, the responding trafficmanagement device can access the table 340 to retrieve the neededinformation. Also, if the incoming data packet or data event is notlisted in the table 340 and the data event or packet must be associatedwith a destination, the responding traffic management device can updatethe table 340. Subsequently, each of the traffic management devices310-330 will be able to direct such data events or packets to theappropriate destination. As described below, implementations of thepresent disclosure facilitate efficient traffic management by allowingone of the traffic management devices 310-330 to update a portion of thetable 340 without locking portions of the table 340. As a result, theother traffic management devices will be able to continue tosimultaneously direct other data events or packets, make other updatesto the table 340, thereby not delaying or dropping packets as a resultof encountering locks on portions of the table 340.

FIG. 3B illustrates a componentized implementation of a trafficmanagement system 350 including a plurality of traffic managementcomponents including component #1 360, component #2 370, throughcomponent #N 380. Such an implementation may be a rack-based system inwhich the components 360-380 are blade-type components that can beinstalled in the rack system to provide for flexible scaling of thetraffic management system 350. The components 360-380 each may include atraffic management device configured to handle data event or packetswitching and control to manage both data events or packets that areassociated with destinations and determine destinations for data eventsor packets that are not already associated. Alternatively, each of thecomponents 360-380 may include a switching component or a controlcomponent to handle the directing of data events or packets associatedwith destinations and directing of data events or packets that are notalready associated, respectively, as previously described.

In an implementation of a traffic management system 350, as in theimplementation of the traffic management system 300 of FIG. 3A, thecomponents 360-380 access a common table 390. As previously describedwith reference to the traffic management system 300 of FIG. 3A, each ofthe components 360-380 will be able to direct data events or packets tothe appropriate destination even if previously processed data events orpackets associated with the same destination were previously processedby another component. As described below, implementations of the presentdisclosure facilitate efficient traffic management by allowing thecomponents 360-380 to update portions of the table 390 without lockingportions of the table 390 to the other component. Thus, for example, aswitching component will be able to access the table 390 to direct dataevents or packets even as a control component is updating the table 390.

Examples of Lockless Atomic Table Updating: One-Dimensional Table

FIGS. 4A-6B illustrate examples of implementations of lockless atomicupdating in the context of a one-dimensional table. The illustrationsboth serve to describe operation of implementations of lockless atomicupdating in a one-dimensional case and provide a simple context in whichto lockless atomic updating. However, as described in subsequentfigures, implementations of lockless atomic updating may be used withtables for two or more dimensions.

FIG. 4A illustrates an implementation of a table system 400A.

The table system 400A may be implemented in the memory of a hardwareand/or software-based device to facilitate the management of datapackets or other incoming data events 402. The events 402 will bedirected by one or more traffic management entities, represented in FIG.4A by entity #1 410 and entity #2 420. The entities 410 and 420 may beimplemented in hardware and/or software, examples of which wereillustrated and described above in connection with FIGS. 3A and 3B. Inthe following examples, the entities 410 and 420 both support controlfunctions in the sense that each can update the table 430A.

In the implementation of FIG. 4A, entity #1 410 is associated with aclassifier table #1 412A and an open position buffer #1 418A. Entity #2420 is associated with a classifier table #2 422A and an open positionbuffer #2 428A. The classifier tables 412A and 422A and the openposition buffers for the separate entities 410 and 420 could be part ofthe same hardware or memory device. However, logically, the classifiertables 412A and 422A and open position buffers 418A and 428A aredepicted as separate because, in one implementation, the entities 410and 420 can separately and simultaneously update these tables andbuffers without the operation of entity #1 410 interfering with that ofentity #2 420, and vice versa. Also, while the classifier tables 412Aand 422A and open position buffers 418A and 428A are shown as separatefrom each other and separate from their respective entities 410 and 420,the open position buffers 418A and 428A could be integrated with theclassifier tables 412A and 422A for the respective entities 410 and 420.In addition, the classifier tables 412A and 422A and/or open positionbuffers 418A and 428A could be integrated with their respective entities410 and 420.

As will be described below, each of the entities 410 and 420 manage amutually disjointed set of classifier indices each of which, in turn, isused to represent one of a set of mutually disjointed positions in thetable 430A. The mutually disjointed classifier indices and positionsavoid contention in allowing the entities 410 and 420 to separately andsimultaneously update portions of the table 430A. The classifier indicesare managed through the use of classifier tables 412A and 422A. Inimplementations of the present disclosure, each classifier index in theclassifier table will be associated with a position within the table430A, as will be described below.

In the example of FIGS. 4A-6B, the classifier tables 412A and 422A eachhave three positions, thus accommodating three classifier indices to bedetermined or derived for the incoming data events or packets 402 and tobe managed by each of the respective entities. In the implementation ofFIG. 4A, the classifier index is determined by position within theclassifier tables. The first position in classifier table 412A atposition (0) represents the first classifier index, while positions (1)and (2) represent the second and third classifier indices, respectively,managed by entity #1 410. The first position in classifier table 422A atposition (3) represents the first classifier index managed by entity #2420, or the fourth classifier index overall, and is thus labeled asposition (3). Positions (4) and (5) represent the second and thirdclassifier indices, managed by entity #2 420, or the fifth and sixthoverall classifier indices managed by both entities 410 and 420.

As previously mentioned, each of the entities 410 and 420 also isassociated with an open position buffer 418A and 428A, respectively.According to an implementation of the present disclosure, for each ofthe entities 410 and 420, an open position in the table 430A ismaintained that is not simultaneously listed in the classifier tables412A and 422A. Again, as will be described below, when one of theentities 410 and 420 updates the table 430A, that entity will store theupdate in its available, open position, then will associate the updated,formerly-open position with the classifier index for the position thatwas just updated. The position that was just updated then becomes thenew open position that will be identified in the respective openposition buffer. As a result, the open position for each entity can beatomically updated without locking any of the other positions in thetable 430A.

For purposes of the following examples of FIGS. 4B-6B, the table 430A isa one-dimensional table that, in this example, includes a plurality ofpositions 432. Specifically, the table 430A includes positions in theform of eight columns, including column A 450, column B 451, column C452, column D 453, column E 454, column F 455, column G 456, and columnH 457. The eight positions 432 within table 430A provide four mutuallydisjointed positions to be managed by each of the entities 410 and 420,including for each entity three positions that will be active and onethat will be open for updates.

FIG. 4B shows a table system 400B in which the tables and buffers arepopulated with sample data that will be used in the following examplesto illustrate the operation of implementations of the presentdisclosure. Data event #0 404 is associated with a classifier index 2that is managed by the first entity. The classifier index associatedwith each event can be determined or identified in a number of ways. Forexample, the classifier index may be determined by reading a designatedportion of the event, such as a predetermined range of bits in theevent. Alternatively, the classifier index may be determined by applyinga function, such as a hash function to a portion of the event, theportion including some or all of the event. The output of that functionwill yield a classifier index. From the resulting classifier index, itis determined which of the entities 410 and 420, each of which manage amutually disjointed set of classifiers indices, will process the event404. Because event 404 is associated with classifier index 2, it will beprocessed by entity #1 410, as described in the following figures.

In the example of FIGS. 4B-6B, the first four positions in the table430B are associated with entity #1 410, while the last four positionsare associated with entity #2 420. This association, however, isarbitrary. Thus, for example, entity #1 410 could have been associatedwith the last four positions in table 430B, the positions associatedwith each of the entities 410 and 420 could have been interleaved, etc.

Classifier table #1 412B includes three positions in the table 430Bassociated with each of the classifier indices. The classifier index (0)is associated with position B, the second classifier index (1) isassociated with position C, and the third classifier index (2) isassociated with position D. Open position buffer #1 418B is associatedwith position A 450, the remaining, unused position in the table 430Bassociated with entity #1 410. Classifier table #2 422B includes threepositions in the table 430B associated with each of its classifierindices. Its indices, the overall fourth (4), fifth (5), and sixth (6)indices, are associated with positions F, G, and H, respectively. Openposition buffer #2 428B is associated with position E 454, theremaining, unused position in the table 430B associated with entity #2420. Although the open positions in FIG. 4B are each shown to be thefirst of the positions associated with each of the entities, this choicealso is arbitrary.

The table 430B includes two initial data entries, including M 440 inposition D 453, and N 442 in position G 456. These data entries arearbitrary and included only to help illustrate the operation ofimplementations of the present disclosure

FIGS. 4C-6B depict operation of implementations of lockless atomicupdating in a one-dimensional table. (FIGS. 7A-8B illustrate operationof implementations of lockless atomic updating in a two-dimensionaltable.) In these examples, operations to read from or write to one ofthe tables or buffers are represented by arrows labeled with referencenumbers. The following description uses the reference numbers to referto the operations depicted by the arrows.

FIG. 4C shows a table system 400C handling the first aspects ofprocessing the data packet or event 404 according to an implementationof the present disclosure. The classifier index associated with the datapacket or event #0 404 is determined by reading from the data packet orevent 404 or otherwise applying a function to contents of the event 404.The classifier index associated with the data packet or event 404determines which of the entities will handle the update. The classifierindex associated with the data packet or event 404 could be determinedby entity #1 410, by another entity, or by other component that wouldthen pass the data packet or event 404 to entity #1 410. The data packetor event 404, event #0, is associated with a classifier index 2 in thisexample. Because classifier index 2 is one of the classifier indiceshandled by entity #1 410, the data packet or event 404 is handled byentity #1 410.

At 480, entity #1 410 receives the event 404 and reads that classifierindex 2 is associated with the event 404. At 482, entity #1 410 consultsclassifier table #1 412B to determine what position in the table 430B isassociated with the classifier index. At 484, entity #1 410 reads fromclassifier table #1 412B that classifier index 2 is associated withposition D in the table 430B. At 486, entity #1 410 consults openposition buffer #1 418B to determine what open position is available toentity #1 410 to apply the update. The open position buffer #1 indicatesthat position A is the currently open position.

Referring now to FIG. 4D, data packet or event 404 may not currently beassociated with a destination in this example. Thus, an update mayinclude storing in the table 430D a destination where subsequent datapackets or events 404 associated with the same classifier index may berouted. The destination may be determined as the result of someload-balancing or another process. In this example, the destination orother update applied is O 444.

At 490, the update O 444 is written to position a 450 in the table 430D.Because the event 404 was associated with a classifier index which inturn was associated in classifier table #1 412B with position D, onemight conclude that the update would be applied to position D 453 in thetable 430D. However, according to an implementation of the presentdisclosure, when an update is made to the table 430D, the update isapplied to the open position available to the entity making the update.Thus, in this case entity #1 410 applies the update to position A 450which is the open position indicated by open position buffer in #1 418B.Because the update is applied to the open position and not the currentposition associated with the classifier index, any other entity needingto access information in the current position associated with classifierindex can do so; because the update is applied to another position, thecurrent position remains unlocked. Advantages of this lockless updateare further described below with reference to FIG. 7C.

FIG. 4E shows a table system 400E in which the classifier table and openposition buffer are themselves updated to reflect the update applied tothe table 430D. At 494, entity #1 410 updates classifier table #1 412Eto show that classifier index 2 is now associated with position A toreflect the update that was made to position A 450 in table 430D. Nowthat the update has been applied to the table 430D and reflected inclassifier table #1 412E, the position formerly associated withclassifier index 2, position D 453, is available as the new openposition available to entity #1 410. At 496, open position buffer #1418E is updated to reflect that position D 453 is now the open position.With the tables and the open position buffer updated, the table system400E is now fully updated and ready to continue processing the datapacket(s) or event(s).

FIGS. 5A and 5B depict the processing of a next data packet or event tofurther illustrate the operation of an implementation of lockless atomicupdating. The views of FIGS. 4B-4E are condensed into FIGS. 5A-5B in theinterest of conciseness.

FIG. 5A shows table system 500A, that begins with the state of tablesystem 400E. In FIG. 5A, a next data packet or event, event #1 504, isprocessed according to an implementation of the present disclosure. At580, entity #1 510 receives event #1 504 and determines that event #1504 is associated with classifier index 1. At 582, entity #1 510 refersto classifier table #1 512A. At 584, entity #1 determines thatclassifier index 1 is currently associated with position C. At 586,entity #1 510 reads from open position buffer #1 518A that the currentopen position is position D. Thus, at 590, instead of writing theupdate, P 546, to position C associated with classifier index 1, theupdate is written to the currently open position, position D 553. As aresult, any other components or entities that might desire to read fromposition C 552 will be able to do so because entity #1 510 writes theupdate to the open position, position D 553.

FIG. 5B shows table system 500B, in which the relevant classifier tableand open position buffer are updated to reflect the update made to thetable 530A. At 594, classifier table #1 512B is updated to reflect thatclassifier index 1 is now associated with position D, the previouslyopen position in which the update was applied to the table 530A. At 596,open position buffer #1 518B is updated to reflect that the new openposition is position C, the position that was replaced in the previousupdate.

FIGS. 6A and 6B depict one further example of updates to asingle-dimension table to illustrate updates being made by multipleentities. FIG. 6A shows a table system 600A receiving event #2 604associated with classifier index 0, which is associated with entity #1610, and event #3 606 associated with classifier index 5, which isassociated with entity #2 620. To distinguish between the actions ofeach of the entities 610 and 620, actions associated with entity #1 610continue to be referenced with even reference numbers, while the actionsassociated with entity #2 are referenced with odd reference numbers.

At 680, entity #1 610 receives event #2 604 and determines that event #2604 is associated with classifier index 0. At 682, entity #1 610 refersto classifier table #1 612A. At 684, entity #1 determines thatclassifier index 0 is currently associated with position B. At 686,entity #1 610 reads from open position buffer #1 618A that the currentopen position is position C. Thus, at 690, instead of writing theupdate, Q 648, to position B 651 associated with classifier index 0, theupdate is written to the currently open position, position C 652. Duringthis time, however, any other components or entities that might desireto read from position B 651 will be able to do so because entity #1 610atomically writes the update to the open position, position C 652,ensuring that position B 651 remains unlocked and available.

While entity #1 610 applies the update motivated by event #2 604, entity#2 620 may simultaneously or nearly simultaneously apply an updatetriggered by event #3 606. At 681, entity #2 620 receives event #3 606and determines that event #3 606 is associated with classifier index 5.At 683, entity #2 620 consults classifier table #2 622A. At 685, entity#2 620 determines that classifier index 5 is currently associated withposition H. At 687, entity #2 620 determines from open position buffer#2 628A that the current open position available to entity #2 620 isposition E. Thus, at 691, instead of writing the update, R 649, toposition H 657 associated with classifier index 5, entity #2 620 appliesthe update to the currently open position for entity #2 620, position E654. Again, while this update is applied, other components or entitiesthat have reason to access position H 657 are able to do so; entity #2620 atomically writes the update to its open position in table 630B,position E 654, leaving position H 657 unlocked and accessible.

Again, while updates are being applied by entity #1 610 and entity #2620, other components or entities may need to access the table 630B. Forexample, the values written to the table, from O 644 to R 649, may haveinformation, all or portions of which, provide a destination for a datapacket received by the traffic management device table system 600A.Thus, if entity #2 620 seeks to find a destination for a packet or eventthat is already associated with a destination, it may read destinationinformation stored in the data at position B 651 that is not related toor hindered by the update being applied by entity #1 610.Implementations of lockless atomic updating allow for entities 610 and620, which may be control components configured to assign destinationsto previously unassociated packets or events, to update the table 630Awhile switching components have full access to the table 630A to directpreviously associated events or packets.

FIG. 6B shows table system 600B, in which the classifier tables 612B and622B and open position buffers 618B and 628B are updated to reflect theupdate made to the table 630A. At 694, entity #1 610 updates classifiertable #1 612B to reflect that classifier index 0 is now associated withposition C 652, the previously open position in which the update wasapplied to the table 630A. At 696, entity #1 610 updates open positionbuffer #1 618B to indicate that the new open position available toentity #1 610 for its next update is position B, the position that wassuperseded in the previous update.

While entity #1 610 updates classifier table #1 612B and open positionbuffer #1 618B, perhaps simultaneously, entity #2 620 updates classifiertable #2 622B and open position buffer #2 628B to reflect the updateentity #2 620 just applied to the table 630B. At 695, entity #2 620updates classifier table #2 622B to indicate that classifier index 5 isnow associated with position E 654, the previously open position priorto the update. At 697, entity #2 620 updates open position buffer #2628B to reflect that the open position now available to entity #2 620 isposition H.

Examples of Lockless Atomic Table Updating: Two-Dimensional Table

FIGS. 7A-8B illustrate examples of implementations of lockless atomicupdating in the context of a two-dimensional table. Implementations oflockless atomic updating may be applied to tables or other data storesof any dimension. Also, as described below, the indirection in accessingthe table facilitated by the classifier tables may be used in more thanone dimension to allow atomic updating to be applied in multipledimensions if the supporting system allows such granularity of access.

The two-dimensional examples lend themselves to illustration of howrouting of packets and data events is commonly handled: informationregarding the routing of packets/events commonly is stored in atwo-dimensional table, and the information needed to route a particularpacket/event may be found in a cell in a particular column at aparticular row. The column and row address of a particular cell can beread from the packet/event or can be derived from the packet/event byapplying a hash function to some or all of the data content of thepacket/event.

Using an implementation of lockless atomic updating, a selected columnmay be updated to reflect, for example, the association of a destinationwith a previously unassociated packet/event. As explained below, theupdate is applied by copying the contents of the current column to theopen column and then updating the row of that open column to include thenew association information. While the update is being applied in acurrently open column, switching components seeking to routepackets/events already associated with destinations are able to accessother rows of the current column, at its current position. Thus, whilethe update is being atomically applied to the data from the currentcolumn in another (i.e., open) position in the table, the existinginformation in the current column remains unlocked for access. Becausethat column remains unlocked, components may access that information toroute packets or events without delay and without dropping packets. Oncethe update is complete, the classifier table or tables are updated, andcomponents seeking to route events associated with that classifier indexare then directed to the updated column in the table. Thus, componentsseeking to route events already associated with destinations, includingevents newly associated in the most recent update, can obtain thedesired routing information from the updated column.

FIGS. 7A-8B illustrate table systems using a somewhat differentimplementation than that illustrated in FIGS. 4A-6B. As already noted,the tables are two-dimensional tables. Moreover, instead of usingseparate open position buffers, the classifier tables include a locationto identify the positions in the tables currently open for the entitiesto apply updates. Also, unlike the classifier tables in the previousexamples that were presented in the form of a one-dimensional array, theclassifier tables in the following examples are presented astwo-dimensional tables to associate a classifier index with a positionin the table. As previously mentioned, the classifier tables also couldbe integrated within their respective entities, although that variationis not shown in FIGS. 7A-8B. In any case, the preceding and followingexamples are provided for illustration, not limitation, andimplementations according to the present disclosure are not limited bydetails provided by way of illustration.

FIG. 7A shows a table system 700A configured to allow entities 710 and720 to process a series of data packets or other events 702 to update atwo-dimensional table 730A. Entity #1 710 is associated with classifiertable #712A, which has a number of classifier indices 714 that can beassociated with positions of the table 730A in positions in a firstdimension 732 of the table 730A. The positions in the first dimension732 are columns including column C0 750, column C1 751, column C2 752,column C3 753, C4 754, column C5 755, column C6 756, column C7 757 ofthe table 730A. The table 730A also includes in a second dimension 734 aplurality of rows, including row R0 770, row R1 771, row R2 772, row R3773, and row R4 774.

Entity #1 710 is associated with classifier table #1 712A and entity #2720 is associated with classifier table #2 722A. As previouslydescribed, classifier tables 712A and 722A each include a location toidentify the current open positions in the table associated with each ofthe entities to apply updates. In implementations according to thepresent disclosure, each of the entities is individually associated withan open position available for its use. Although a pool of openpositions could be made available to be used collectively by theentities, this would create the possibility of contention betweenentities for the same open position. As a result, the pool of openpositions would have to employ a locking system for the open positionswould involve the complexity of a locking system and the possibility ofdelays that implementations of lockless atomic updating seek to avoid.

Entity #1 710 is associated with classifier indices A, B, and C andmanages columns C0 750-C3 753, while entity #2 720 is associated withclassifier indices D, E, and F and manages columns C4 754-C7 757. Aspreviously described, implementations according to the presentdisclosure associated mutually disjoint sets of classifier indices andpositions with each of the entities to avoid contention and to supportlockless updating.

In the examples of FIGS. 7A-8B, first and second classifier indicesassociated with each of the events 702 are determined by reading aportion of each of the events or by deriving the classifier indices byapplying one or more functions, such as hash functions, to the contentsof the events 702. In these examples, first classifier indices will beassociated with columns in the first dimension 732 of the table 730Awhile second classifier indices will be associated with rows in thesecond dimension 734 of the table 730A. The following examples show thatan open position in the first dimension 732 is used atomically to applyupdates to single columns, while the second classifier index is used toaccess locations within the columns. Alternatively, however, the updatescould be applied in open rows instead of open columns. In otheralternatives, classifier tables could be made available in multipledimensions to allow atomic updating of individual cells.

FIG. 7B shows a table system 700B in which the tables are populated withsample data that will be used in the following examples to illustratethe operation of implementations of the present disclosure. Data event#0 704 is associated with a first classifier index B that is managed byentity #1 710. Data event #0 also is associated with a second classifierindex that corresponds with R1. In the examples of FIGS. 7A-8B,classifier tables are used in only one dimension, the first dimension732 (FIG. 7A), so the second classifier indices identify a location inthe table 730B rather than a classifier index associated with a positionthrough the use of a classifier table. Classifier table #1 712Bcurrently associates classifier index A with position C0, classifierindex B with position C1, and classifier index C with position C2. Thetable 730B includes three initial data entries, including U 740, V 742,and W 743. These data entries are arbitrary and included only to helpillustrate the operation of implementations of the present disclosure.

FIG. 7C shows a table system 700C handling the first aspects ofprocessing the data packet or event 704 according to an implementationof the present disclosure. At 780, entity #1 710 receives the event 704and reads that the first classifier index is classifier index B and thesecond classifier index is R1. At 782, entity #1 710 consults classifiertable #1 712B to determine what position currently is associated withclassifier index B and to determine what is the currently open positionavailable to it to apply an update. At 784, from classifier table #1712B, entity #1 determines that classifier index B is associated withcolumn C1 and that column C6 is the current open position.

In an implementation of lockless atomic updating in a multi-dimensionaltable as shown in FIG. 7C, locations in the position identified by theclassifier index of the event being processed are first copied torespective locations in the open position. In updating the table 730C inresponse to event #0 704, only one or some of the row locations in theposition currently associated with the classifier index may be updated.However, after the update is made available upon updating the classifiertables as previously described, the information that was not updatedshould continue be made available in the table.

Thus, at 788, information stored in the rows of the position currentlyassociated with the classifier index of event #0 704, which in this caseis column C1 751, is copied to the open position column, column C6 756.For example, data V 742, in row R0 770 of column C1 751, is copied to acorresponding row location in row R0 770 of column C6 756. At 790, theupdated data, X 746, is then stored in the open position column C6 756in row R1 771, as specified by the second classifier index of event #0704. As a result, column C6 756 in the current open position nowincludes the data not being updated from the current position, V 742,and the updated data, X 746.

FIG. 7D shows a table system 700D in which entity #1 710 updatesclassifier table #1 712D reflect the update applied to the table 730C.At 792, the updates are applied to show that classifier index B is nowassociated with column C6 756 to reflect the update that was made incolumn C6 of the table 730C. In addition, the open position space 718Din classifier table #1 712D is updated to show that column C1 is now theopen position available to receive the next update.

FIGS. 8A-8B illustrate an example in which more than one entitysimultaneously or nearly simultaneously update the table 830A. Entity #1810 and Entity #2 820 are associated with respective classifier tables812A and 822A and manage designated classifier indices and positions inthe table 830A as described with reference to FIGS. 7A-7D. The table830A includes a plurality of columns C0 850 through C7 857 and aplurality of rows R0 870 through R4 874.

At 880, entity #1 810 receives event #1 804 and determines that it isassociated with a first classifier index A and a second classifier indexR3. At 884, entity #1 810 refers to classifier table #1 812A todetermine what position in the table 830A is currently associated withclassifier index A and what is the current open position. At 886, entity#1 810 determines that classifier index A is currently associated withcolumn C0 and that the current open position is column C1. At 888, anydata populating column C0 850, that is currently associated with thefirst classifier index A, is copied to the corresponding row in the openposition column C1 851. At 890, new data associated with event #1 804,in the form of Y 846, is written to row R3 873, as indicated by thesecond classifier index, in column C1 851.

At or about the same time, at 881, entity #2 820 receives event #2 806and determines that it is associated with a first classifier index F anda second classifier index R1. At 885, entity #2 820 refers to classifiertable #2 822A to determine what position in the table 830A is currentlyassociated with classifier index F and what is the current openposition. At 887, entity #2 820 determines that classifier index F iscurrently associated with column C5 and that the current open positionavailable for entity #2 820 is column C7. At 889, data populating columnC5 856 is copied to the corresponding row in the open position column C7857. At 891, new data associated with event #2 806, in the form of Z847, is written to row R1 873, as indicated by the second classifierindex of event #2 806, in column C7 857.

FIG. 8B shows table system 800B, in which the entities 810 and 820update classifier tables 812B and 822B, respectively, to reflect theupdates made to the table 830A. At 892, entity #1 810 updates classifiertable #1 812B to reflect that classifier index A is now associated withposition C1 and the open position is now C0. At 893, entity #2 820updates classifier table #2 822B to reflect that classifier index F isnow associated with position C7 and the open position available forentity #2 820 is now C5.

Exemplary Modes of Lockless Atomic Updating

FIGS. 9 and 10 illustrate modes of updating single-dimension andtwo-dimension tables, respectively, according to implementations of thecurrent disclosure. As previously described, implementations accordingto the present disclosure can be used to update tables more than twodimensions. In addition, classifier tables could be used to apply andcontrol updates in more than one dimension of a table to allow locklessatomic updating at a cell level, rather than just at a column or rowlevel.

FIG. 9 presents a flow diagram 900 illustrating one mode of updating aone-dimension table. At 910, a classifier is identified for a data eventor packet initiating an update to the table. At 920, a classifier tableis accessed to identify a table position associated with or referencedby the classifier index. At 930, an open position in the table availableto receive the update is identified. At 940, a new value is stored inthe open position. As exemplified in FIGS. 4A-6B, a new value may bestored in the open position without copying data stored in the positionbeing updated, but the new value also may include some data that iscopied from the position being updated.

At 950, the classifier table is updated to associate the classifierindex with the previously open position. At 960, to facilitate the nextupdate, the referenced position whose contents were superseded in theupdate is now identified as the open position available to receive thenext update. The process illustrated by the flow diagram 900 may berepeated, updating positions referenced by the classifier indexdetermined from the data event or packet, storing the updates in theopen position, and then making the superseded position available for thenext update. As the updates are being made, the position referenced bythe classifier index remains unlocked and available for access.

FIG. 10 presents a flow diagram 1000 illustrating a mode of updating atwo-dimensional table. The process of flow diagram 1000 varies from thatof the flow diagram 900 (FIG. 9) to reinforce that the modes presentedin this description are provided by way of illustration, not limitation.

At 1010, an event, such as a data packet or other data event, isdetected by an entity configured to apply updates to the table. At 1020,a first classifier index is identified from the event. At 1030, a secondclassifier index is identified from the event. As previously described,each of the classifier indices may be read from or derived from thecontent of the event. At 1040, a classifier table is accessed todetermine the position in the first dimension of the table correspondingwith the first classifier index. At 1050, an open position available tothe entity to update the table is identified. As previously described,the update will be applied in the open position.

At 1060, any existing contents of the position referenced by the firstclassifier index are copied to corresponding rows or other locations inthe open position. At 1070, a new value indicated by or for the dataevent or packet is stored in the open position at a position indicatedby the second classifier index. At 1080, the classifier table is updatedto associate the first classifier index with the open position that hasreceived the update. At 1090, the position that previously wasreferenced by the first classifier index is now identified as the openposition to receive the next update.

CONCLUSION

Although exemplary implementations have been described in languagespecific to structural features and/or methodological acts, it is to beunderstood that the appended claims are not necessarily limited to thespecific features or acts previously described. Rather, the specificfeatures and acts are disclosed as exemplary implementations.

What is claimed is:
 1. A traffic manager device configured to provideuninterrupted access to a network traffic handling table during tableupdates, the device comprising: a memory configured to store a set ofprocessor executable instructions; a network transceiver configured tohandle network traffic; a processor coupled to the network transceiverand the memory, the processor configured to execute the set of storedprocessor executable instructions which causes the processor to performa method, the method further comprising: identifying a first classifierindex associated with a data packet received via the network interface;identifying a second classifier index associated with the data packet;accessing a first classifier table to determine a current position in afirst dimension of a network traffic handling table associated with thefirst classifier index; determining an open position in the firstdimension of the network traffic handling table; copying existing packethandling data from the current position to one or more correspondinglocations in the open position in the first dimension of the networktraffic handling table; storing updated packet handling data within theopen position in the network traffic handling table at a seconddimension location indicated by the second classifier index; associatingthe open position with the first classifier index in the firstclassifier table, wherein the open position becomes a new currentposition associated with the first classifier index; designating thecurrent position previously associated with the first classifier indexas a new open position in the network traffic handling table; anddetermining the second dimension location indicated by the secondclassifier index by referencing a second classifier table associating aplurality of second dimension locations with a plurality of secondclassifier indices.
 2. The traffic manager device of claim 1, wherein atleast one of the first classifier index or the second classifier indicesare identified from the data packet by one of: reading a segment of thedata packet; or applying a function to at least a portion of the datapacket.
 3. The traffic manager device of claim 2, wherein the functionapplied to at least the portion of the data packet includes a hashfunction.
 4. A traffic manager device configured to provideuninterrupted access to a network traffic handling table during tableupdates, the device comprising: a memory configured to store a set ofprocessor executable instructions; a network transceiver configured tohandle network traffic; a processor coupled to the network transceiverand the memory, the processor configured to execute the set of storedprocessor executable instructions which causes the processor to performa method, the method further comprising: identifying a first classifierindex associated with a data packet received via the networktransceiver; identifying a second classifier index associated with thedata packet; accessing a first classifier table to determine a currentposition in a first dimension of a network traffic handling tableassociated with the first classifier index; determining an open positionin the first dimension of the network traffic handling table; copyingexisting packet handling data from the current position to one or morecorresponding locations in the open position in the first dimension ofthe network traffic handling table; storing updated packet handling datawithin the open position in the network traffic handling table at asecond dimension location indicated by the second classifier index;associating the open position with the first classifier index in thefirst classifier table, wherein the open position becomes a new currentposition associated with the first classifier index; and designating thecurrent position previously associated with the first classifier indexas a new open position in the network traffic handling table, whereinthe network traffic handling table includes a destination tableconfigured to store entries containing addresses of one or moreresources to which one or more other data packets are to be directed,wherein an address of a resource to which an additional data packet isto be delivered is retrieved from the destination table based on aclassifier index associated with the additional data packet.
 5. Anon-transitory machine readable medium having stored thereoninstructions for providing uninterrupted access to a network traffichandling table during table updates, comprising machine executable codewhich when executed by at least one processor, causes the processor toperform steps comprising: identifying a first classifier indexassociated with a data packet received by at least one of a plurality oftraffic management devices; determining from a first classifier table aninitial table position in a first dimension of a network traffichandling table, the first classifier table associating classifierindices with table positions such that the initial table position isassociated with the first classifier index; determining an initial opentable position in the first dimension of the network traffic handlingtable; storing information associated with the data packet in theinitial open table position in the network traffic handling table; andassociating the initial open table position with the first classifierindex in the first classifier table.
 6. The medium as set forth in claim5, further comprising designating the initial table position previouslyassociated with the first classifier index as an updated open positionfor the network traffic handling table.
 7. The medium as set forth inclaim 6, further comprising maintaining an indication of the updatedopen position in the network traffic handling table.
 8. The medium asset forth in claim 5, further comprising: identifying a secondclassifier index associated with the data packet; determining a secondinitial table position in the network traffic handling table in a seconddimension of the network traffic handling table such that the secondinitial table position is associated with the second classifier index;and upon storing the information associated with the data packet in theinitial open position in the network traffic handling table, storing theinformation associated with the data packet at the second initial tableposition of the second dimension in the initial open position in thenetwork traffic handling table.
 9. The medium as set forth in claim 8,wherein the first dimension of the network traffic handling tableincludes a plurality of columns and the second dimension of the networktraffic handling table includes a plurality of rows.
 10. The medium asset forth in claim 8, further comprising, before storing the informationassociated with the data packet in the initial open position in thenetwork traffic handling table, copying existing data from the initialtable position to one or more corresponding positions in the initialopen table position of the network traffic handling table.
 11. Themedium as set forth in claim 8, wherein at least one of the firstclassifier index and the second classifier index are identified from thedata packet by one of reading the first classifier index from a segmentof the data packet or deriving the classifier index from the data packetby applying a function to at least a portion of the data packet.
 12. Themedium as set forth in claim 11, wherein the function applied to atleast the portion of the data packet includes a hash function.
 13. Themedium as set forth in claim 5, wherein the network traffic handlingtable includes a destination table configured to store entriescontaining addresses of one or more resources to which one or more datapackets are to be directed, such that an address of a resource to whichan additional data packet is to be delivered is retrieved from thedestination table based on a classifier index associated with theadditional data packet.
 14. The medium as set forth in claim 5, furthercomprising allowing multiple traffic management devices to update thenetwork traffic handling table, wherein: the multiple traffic managementdevices manage mutually exclusive sets of first classifier indices andinitial open table positions within the network traffic handling tablessuch that the first classifier indices and initial open table positionsbeing managed within the network traffic handling table cannot beupdated by another traffic management device; and the multiple trafficmanagement devices determine the initial table position associated withthe first classifier index in the first dimension of the network traffichandling table by applying one of: a dedicated classifier tablededicated for each of the multiple traffic management devices; or adedicated portion of the first classifier table for each of the multipletraffic management devices.
 15. A method to provide uninterrupted accessto a network traffic handling dataset during dataset updates, the methodcomprising: identifying, by a network traffic management computingentity, a first classifier index associated with a data packet receivedby one of a plurality of traffic management entities; determining, bythe network traffic management computing entity from a first classifierdataset, an initial dataset position in a first dimension of the networktraffic handling dataset, the first classifier dataset associatingclassifier indices with dataset positions such that the initial datasetposition is associated with the first classifier index; determining, bythe network traffic management computing entity, an initial open datasetposition in the first dimension of the network traffic handling dataset;storing, by the network traffic management computing entity, informationassociated with the data packet in the initial open dataset position inthe network traffic handling dataset; and associating, by the networktraffic management computing entity, the initial open dataset positionwith the first classifier index in the first classifier dataset.
 16. Themethod of claim 15, further comprising designating, by the networktraffic management computing entity, the initial dataset positionpreviously associated with the first classifier index as an updated openposition for the network traffic handling dataset.
 17. The method ofclaim 16, further comprising maintaining, by the network trafficmanagement computing entity, an indication of the updated open positionin the network traffic handling dataset.
 18. The method of claim 15,further comprising: identifying, by the network traffic managementcomputing entity, a second classifier index associated with the datapacket; determining, by the network traffic management computing entity,a second initial dataset position in the network traffic handlingdataset in a second dimension of the network traffic handling datasetsuch that the second initial dataset position is associated with thesecond classifier index; and upon storing the information associatedwith the data packet in the initial open position in the network traffichandling dataset, storing, by the network traffic management computingentity, the information associated with the data packet at the secondinitial dataset position of the second dimension in the initial openposition in the network traffic handling dataset.
 19. The method ofclaim 18, wherein the first dimension of the network traffic handlingdataset includes a plurality of columns and the second dimension of thenetwork traffic handling dataset includes a plurality of rows.
 20. Themethod of claim 18, further comprising, before storing the informationassociated with the data packet in the initial open position in thenetwork traffic handling dataset, copying, by the network trafficmanagement computing entity, existing data from the initial datasetposition to one or more corresponding positions in the initial opendataset position of the network traffic handling dataset.
 21. The methodof claim 18, wherein at least one of the first classifier index and thesecond classifier index are identified from the data packet by one ofreading, by the network traffic management computing entity, the firstclassifier index from a segment of the data packet or deriving, by thenetwork traffic management computing entity, the classifier index fromthe data packet by applying a function to at least a portion of the datapacket.
 22. The method of claim 21, wherein the function applied to atleast the portion of the data packet includes a hash function.
 23. Themethod of claim 15, wherein the network traffic handling datasetincludes a destination dataset configured to store entries containingaddresses of one or more resources to which one or more data packets areto be directed, such that an address of a resource to which anadditional data packet is to be delivered is retrieved from thedestination dataset, by the network traffic management computing entity,based on a classifier index associated with the additional data packet.24. The method of claim 15, further comprising allowing, by the networktraffic management computing entity, multiple traffic managemententities to update the network traffic handling dataset, wherein: themultiple traffic management entities manage mutually exclusive sets offirst classifier indices and initial open dataset positions within thenetwork traffic handling dataset such that the first classifier indicesand initial open dataset position being managed within the networktraffic handling dataset cannot be updated by another traffic managemententity; and the multiple traffic management entities determine theinitial dataset position associated with the first classifier index inthe first dimension of the network traffic handling dataset by applyingone of: a dedicated classifier dataset dedicated for each of themultiple traffic management entities; or a dedicated portion of thefirst classifier dataset for each of the multiple traffic managemententities.
 25. A method to provide uninterrupted access to a networktraffic handling table during table updates, the method comprising:receiving, by a network traffic management computing device, a datapacket; identifying, by the network traffic management computing device,a first classifier index associated with the data packet; identifying,by the network traffic management computing device, a second classifierindex associated with the data packet; accessing, by the network trafficmanagement computing device, a first classifier table to determine acurrent position in a first dimension of the network traffic handlingtable associated with the first classifier index; determining, by thenetwork traffic management computing device, an open position in thefirst dimension of the network traffic handling table; copying, by thenetwork traffic management computing device, existing packet handlingdata from the current position to one or more corresponding locations inthe open position in the first dimension of the network traffic handlingtable; storing, by the network traffic management computing device,updated packet handling data within the open position in the networktraffic handling table at a second dimension location indicated by thesecond classifier index; associating, by the network traffic managementcomputing device, the open position with the first classifier index inthe first classifier table, wherein the open position becomes a newcurrent position associated with the first classifier index; anddesignating, by the network traffic management computing device, thecurrent position previously associated with the first classifier indexas a new open position in the network traffic handling table.
 26. Themethod of claim 25, further comprising determining, by the networktraffic management computing device, the second dimension locationindicated by the second classifier index by referencing a secondclassifier table associating a plurality of second dimension locationswith a plurality of second classifier indices.
 27. The method of claim26, wherein at least one of the first classifier index or the secondclassifier indices are identified from the data packet by one of:reading, by the network traffic management computing device, a segmentof the data packet; or applying, by the network traffic managementcomputing device, a function to at least a portion of the data packet.28. The method of claim 27, wherein the function applied to at least theportion of the data packet includes a hash function.
 29. The method ofclaim 25, wherein the network traffic handling table includes adestination table configured to store entries containing addresses ofone or more resources to which one or more other data packets are to bedirected, such that an address of a resource to which an additional datapacket is to be delivered is retrieved from the destination table, bythe network traffic management computing device, based on a classifierindex associated with the additional data packet.